Effects of Early Interventions on Learning, Memory and Neuron Apoptosis of Rats with Hypoxic-Ischemic Brain Damage

Objective To explore the influences of early interventions on learning, memory and neuron apoptosis in the brain of neonatal rats with hypoxic ischemic brain damage(HIBD). Methods (1)A fetal rat model of HIBD was performed by ligating unilateral uterine horn vessel of pregnant SD rat for 15 minutes, the fetuses in the contralateral horn whose uterine horn vessel was not ligated were used as controls, the affected and unaffected fetuses were drived into two groups: the intervention group and the non intervention group. (2)Two intervention groups were kept in an enriched environment for 28 days, the others were kept in a standard condition without early interventions. (3)The brain functional outcomes of these rats were evaluated by water maze test. (4)Terminal deoxy nucleotidyl tranferase mediated d UTP biotin nick end labeling(TUNEL) was used to detect neurons apoptosis in forehead cortex and hippocampus of these rats. Results (1)The scores of water maze test in the intervention group was better than the normal group, there was no difference between the intervention group with HIBD and the normal group, the non intervention group with HIBD was the worst. (2)The median of apoptosis positive neurons in forehead cortex and CA1 region of hippocampus in non intervention group with HIBD were 8 and 9 cells/(1 mm×1 mm) respectively, that were significantly higher than those of intervention group with HIBD 5 and 6 cells/(1 mm×1 mm), normal group 2 and 4 cells/(1 mm×1 mm), and the intervention group 0 and 2 cells/(1 mm×1 mm). (3)There was a correlation between the water maze scores and the numbers of apoptosis neurons in the forehead cortex. Conclusion Early intervention is one of the effective ways for improving learning and memory with the hypoxic ischemic brain damage rats by decrease the ratio of neuronal apoptosis in forehead cortex and hippocampus.